Sand mold and method of treating the same.



UNITED STATES.

PATENT OFFICE.

CHARLES B. JACOBS, OF PORT CHESTER, NEw YORK, ASSIGNOB TO MURRAY ANDJACOBS MANUFACTURING COIPANY, OF NEW YORK, N. Y., A CORPORATION OF NEWYORK.

SAND HOLD AND METHOD OF TREATING THE SAME.

specification-o! ream Patent. Iv I atented Sept. 14, 1915,

I Drawing. Application fled January 4, 1912, Bertal no. 600,491. Renewedm a, 1915. serial m. 41,796.

To all whom it may concern:

Be it known that I, Cmams BJJaoons, a citizen of the United States, anda resident of Port Chester, Westchester county, State of New York, haveinvented certain new and useful Improvements in Sand Molds and 'Methodsof Treating the Same, of which the following is a specification.

This invention relates to the production of sand molds for making metalcastings; and it has for an object the production of mold surfaces,particularly molds formed of unbaked or green sand which are adapted forforming those lands of steel and other castings which ordinarily cannotbe satisfac-. torily made in such molds because of the delicac of themold surface or some part thereo or because of the weight or erosivecharacter of the metal or its tendency to flux with the material in themold and form scabs or scoria or an. objectionable crust on the surfaceof the casting.

In accordance with this invention, a coment is applied (that is, to thewhole of, or a part of, the surface) of a sand mold and dried, saidcement being adapted, when solidified, to make the surface of the moldhard and strong so that it will not disintegrate or be deformed by theeroding action of the metal flowin therethrough or by the weight of themeta and will not unite with the metal so as to form scabs or scoria.

In carrying out the invention, the mold' may be formed in the ordinaryway, and the surface of those parts of the mold which requirestrengthenm are treated with the ocment which may applied as a wash bymeans of a mold swab or it may be sprafyed upon the surface of the moldby means 0 an atomizer or spray can. When the surface of the mold hasthus been moistened with the cement, it is dried to solidify the cement.This is preferably effected in the case of green sand molds with atorch, such as is used in foundries for skin drymg purposes or whetherthe surface be of green or core sand, the dryin operation may beeffected by baking or al owing the mold to stand in the air a suificientlength of time.

The cement which has given the best results is what is herein termed asoluble glass. Such a cement may be formed by combining the oxids ofcertain elements of groups three and four of the periodio table with theoxygen salts of the alkalin metals.

ti soda, and to 125 arts of watermid d gest these with heat. he resultwill be a such, for instance," as

For example, oxids of silicon or boron combmed with the hydrate,carbonate or sulfate of sodium or potassium in various proportions willproduce suitable cements, instances of those having silicon as the basebeing the substances commonly known as waterglass. An mstanoe of such .acement having boron as the base is what may be termed a soluble borlcacid glass. This ma be formed, for example, by digesting wit anequivalent .quantity of water, thrce-or' four molecular equivalents ofboric anhydrid with one molecular uivalent of dium hydrate or one molecuar equivalent 0 v m. I drate.

viscous liquid soluble in water and similar in many of its properties toordinary water ,glass.

The strength of the eementmay be varied according to varying conditionsand accordingto the result desired. For instance, ordinarlly, 1t willrequire a stronger solution of the soluble lass to produce a givendegree of hardness 1n the mold surface with coarse sand than with finesand, and, other conditions being equal, the stronger the solution, theharder the surface produced. It should be observed, however, that, ifthe solution is too strong or of full strength, it will be too viscousand will not readily penetrate the surface of the mold and the dryingprocess may produce blisters. On the other hand, if the solution is veryweak, the hardenin effeet will be correspondingly lessened. rdinarily,thebest results will be produced with a solution having from one to fourparts of zvater to one part: of the full'strength solu- Advantages ofthe invention other than those herein mentioned or suggested will beobvious to those skilled in the art.

It will be understood that the invention in its broader aspects is notlimited to the articular sustances herein specifically described nor tothe use of a simple solution of soluble glass as, if desired, var'ousmold facings,

gowdered graphite, 105 silica, lamp black, or the like, may be mixedtherewith or subsequently apphed to the hardened surfaces to give thedesired character of finish to the castings, and other changes orexpedients may be resorted to without departing from the main principlesof the invention and without sacrificing its chif advantages.

I claim:

1. The method of treating sand molds, which method consists in ap lyinto the sand surface of the mold a ui cement adapted to penetrate intothe mo d sand and to consolidate and harden the surface thereof, andthen drying such surface; whereby the sand .mold is rendered able toresist disintegration, deformation, erosion or chemical action by themolten metal.

2. The method of treating sand molds, which method. consists in applyingto the sand surface of the mold a cement adapted to penetrate the moldsand and harden the surface thereof, and then dr ing such surface;whereby the sand mo d is rendered able to resist injury from the moltenmetal.

3. The method of treating sand molds, which method consists in ap lyingto the sand surface of the mold a soliible lass cement adapted topenetrate the m0 d sand and harden the surface thereof, and then dryingsuch surface; whereby the sand mold is rendered able to resist injuryfrom the molten metal.

4. The method of treating sand molds, which method consists in a plyingto the sand surface of the mold a so ution of water glass adapted toharden the surface thereof, and then drying such surface; whereby thesand mold is rendered able to resist injury from the molten metal.

ment comprising a cementing 1i uid holdin in suspension finely dividedsolid materia such cement adapted to penetrate into the mold sand andharden the surface thereof,

and then drying such surface; whereby the sand mold is rendered able toresist injury from the molten metal.

6. The method of treating sand molds, which method consists in applyinto the sand surface of the mold a liqui orm cement comprisin a solubleglass holding in sus nsion fine y divided solid material, suc cementadapted to penetrate into the mold sand and harden the surface thereof,and then drying such surface; whereby the sand mold is rendered able toresist injury from the molten metal.

7. A sand mold having a surface portion thereof consistin of sandcemented and hardened by a so 'dified soluble glass.

8. A sand mold having a surface portion thereof consistin of sandcemented and hardened by a so idified water glass.

9. A sand mold having a surface portion thereof consistin of sandcemented and hardened by a so idified soluble glass having incor oratedtherein a material more finelyv divided than the mold sand.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

CHARLES B. JACOBS.

Witnesses:

R. R. MURPHY, WM. J. DOLAN.

